Recently, as a destruction of an ozone layer is intensifying together with a rapid environmental pollution, an adverse effect on human health by an ultraviolet (UV) light is also increasing, and thus it is urgent to establish measures for this. UV light is a major factor that causes pigmentation and various pigmented skin disease, and can give rise to a direct impact on an intracellular pigment-producing function to increase the deposition of melanin pigment and can cause freckles and age spots.
In general, UV light means a light having a wavelength of 200˜400 nm in sunlight, and covers about 6% of sunlight reaching a surface of an earth. Depending on a wavelength range and length by UV light, a wavelength in the range of 320˜400 nm is classified as UV-A, a wavelength in the range of 280˜320 nm is classified as UV-B, a wavelength in the range of 200˜280 nm is classified as UV-C, and a light covering 90% or more of the ultraviolet light reaching the surface of the earth is UV-A. Since UV-A has a long wavelength, it is easily penetrated into a deep place of a skin compared to other UVs having different range such as B and C, and thus, causes an immediate tanning after lapse of 1˜2 hours, and also since the wavelength of UV-B is short compared to that of UV-A, UV-B causes a sun burn. Although UV-C is the shortest UV light among the UV lights and does not reach the surface of the earth since it is absorbed by an ozone layer located on a stratosphere, UV-C reaching the surface of the earth is also increasing due to the destruction of the ozone layer as mentioned above, and thus it is urgent to establish measures for this. A short wavelength of UV-C is a direct factor causing a skin cancer, because it has energy much larger than a kinetic energy that molecules of a cell have and thus breaks a molecular bond of DNA, etc.
Sunscreen (agent) or ultraviolet blocking agent used in cosmetics is largely classified into an organic-based UV absorbent (organic UV filter) and an inorganic-based UV scattering agent (physical UV filter).
The organic UV absorber is a compound having a conjugated double bond in a molecule, when it absorbs UV light, it becomes an excited state due to an increase of an electronic energy in a molecule, but immediately emits a heat and fluorescence and then returns a ground state. An absorption wavelength or coefficient, etc. of such UV absorber is changed according to a structure of a product, and mostly absorbs UV-B region. Generally, the compound commonly used as raw material of UV absorbent is Octyl Methoxycinnamate of a family of cinnamic acid, which is represented by a Formula [I] as below:

The compound as described above is a representative organic-based UV absorbent, and since it has an excellent compatibility with silicone oil and can be combined easily with other materials, it is widely used in general.
In addition, a representative ultraviolet light absorber absorbing UV-A region is Butyl Methoxydibenzoylmethane and comprises an aromatic compound having a conjugated double-bond represented by the below Formula [II], like OMC (Octyl Methoxycinnamate). Since it is a raw material having very good blocking effect for UV-A region, when it is used with only small amounts in a formulation, the UV blocking effect can be identified:

On the other hand, an UV scattering agent has a characteristic that it can widely block UV-A and -B regions, with a specificity for a wavelength more than an organic UV absorber. The inorganic UV scattering agent includes Titanium Dioxide, Zinc Oxide, etc., and has a relatively high safety compared to the organic UV absorber.
An organic UV absorber literally has a characteristic of absorbing an ultraviolet light, while an inorganic UV scattering agent has an ultraviolet screening effect by blocking and scattering ultraviolet light. That is, the materials mentioned above are metal salts having a high refractive index, and since they have a high degree of surface reflection for an ultraviolet light, they can effectively scatter the ultraviolet light. Inorganic materials widely used as the inorganic UV scattering agent are illustrated in the below Table 1.
TABLE 1Refractive index of an inorganic UV scattering agentMaterialRefractive indexTitanium Dioxide (Rutile)2.7Titanium Dioxide (Anatase)2.5Chromium oxide2.5Iron oxide2.4Zirconium oxide2.2Zinc oxide1.9Alumina1.8Talc1.6Kaoline1.6Water1.3
In addition, the benefits of such inorganic UV scattering agent are that it has no ultraviolet light screening-lowering effect as time lapses, there are fewer legal restrictions in a limitation for combination than an organic UV absorber, and a safety for a human body is high. Also, the wavelength range which can absorb UV light is broad.
Such inorganic UV scattering agents were used as those having a relatively large particle size (1 μm or less) in the past, but since the material having a large particle size causes the white residue on the skin and is reduced in UV-blocking effect, an ultra-fine inorganic material having a small particle size (0.1 μm or less) is preferred at present. Since the material does not cause the white residue on the skin upon applying to a formulation, and also effectively blocks the UV light range more than a visible light, it is commonly used in sunscreen products.
Sun protection factor (SPF) is an index for representing a blocking effect for UV-B, and is a value for determining as to how long a product can expose a skin to sunlight without causing an erythema phenomenon for the skin. SPF is a value obtained with dividing a minimum erythema dose obtained on the area of skin that are applied with a sunscreen product by a minimum erythema dose obtained with an irradiation of UV-B on the area of skin that are not applied with the sunscreen product, and is represented as below:
  SPF  =                                          A            ⁢                                                  ⁢            Minimum            ⁢                                                  ⁢            erythema            ⁢                                                  ⁢            dose            ⁢                                                  ⁢            of            ⁢                                                  ⁢            a                                                            skin            ⁢                                                  ⁢            applying            ⁢                                                  ⁢            a            ⁢                                                  ⁢            sunscreen            ⁢                                                  ⁢            product            ⁢                                                  ⁢                          (              MED              )                                                                      ⁢                                                  A              ⁢                                                          ⁢              Minimum              ⁢                                                          ⁢              erythema              ⁢                                                          ⁢              dose              ⁢                                                          ⁢              of              ⁢                                                          ⁢              a              ⁢                                                          ⁢              skin                                                                          not              ⁢                                                          ⁢              applying              ⁢                                                          ⁢              a              ⁢                                                          ⁢              sunscreen              ⁢                                                          ⁢              product              ⁢                                                          ⁢                              (                MED                )                                                        
Meanwhile, the Talc refers to a raw stone, is generally a designation, but at present, a crushed power is named as the inorganic powder. Since the Talc has characteristics of a low hardness, high whiteness and low electrical conductivity, it exhibits characteristics of the chemical and thermal inactivation. The Talc is used in a variety of Industrial fields such as a paper manufacture, medicine manufacture, etc., and is commonly used as a main base material in a make-up powder cosmetic in the field of cosmetics.
Recently, there has been a social issue due to detection of asbestos-containing Talc in a product such as baby powder, etc., and thus, a powder make-up cosmetic to which the Talc is not added is being developed by many companies. However, since it has not been known up to now for raw materials in which characteristics such as applicabilities of the Talc to a skin and a press pressure on the powder formulation, etc., can be entirely replaced, the Talc in the powder cosmetics covers a considerable portion.
The Talc for cosmetics is a clay mineral having a formula of Mg3Si4O10(OH)2, and has a layer-like structure positioning a magnesium layer on two (2) silica layers as in a structural model III as shown below. Since an interlayer coupling is predominated by Van der waals force, a binding force is weak more than other minerals. Major producers of the Talc are China, Australia, USA, Korea, France, Italia, etc., and there are differences in quality of the Talc according to a place of origin.

Since such the Talc has a refractive index lower than a white pigment such as titanium oxide and zinc oxide and has a small difference in the refractive index with water or oil, it maintains the state of being transparent or translucent in such media, and thus a hiding (shielding) power is small or less.